Answer :
We know that:
[tex]\begin{gathered} \sqrt{1}=1 \\ \sqrt{4}=2 \\ \sqrt{9}=3 \\ \sqrt{16}=4 \\ \sqrt{25}=5 \\ \sqrt{36}=6 \\ \sqrt{49}=7 \\ \sqrt{64}=8 \\ \sqrt{81}=9 \\ \sqrt{100}=10 \\ \sqrt{121}=11 \end{gathered}[/tex]Now, we can see that since 99 is between 81 and 100, the square root of 99 is between 9 and 10.
[tex]\begin{gathered} \sqrt{81}=9 \\ \sqrt{99}=? \\ \sqrt{100}=10 \end{gathered}[/tex]Answer: between 9 and 10